Disclosed is an animal feed manufacturing method in which powdered fish oil of a main raw material is obtained by processing fishes containing a large amount of docosa hexaenoic acid (DHA) and eicosa pentaenoic acid (EPA). The animal feed manufacturing method includes the steps of adding urea to fish oil together with a monosodium glutamate (MSG) by-product and fermenting the fish oil, separately removing water and phospolipid contained in the fermented fish oil, adding quicklime to the separated fish oil and cooling the quicklime-added fish oil via gumming and salting-out processes, and thereby obtaining powdered animal feed using a cooling roller or presser.